Method of assembling carbon parts by refractory brazing

Abstract

The present invention relates to a method of assembling carbon parts using a braze based on silicon carbide. The invention also relates to the parts assembled using such a method.

The invention claimed is: 
     
       1. A method for joining at least two carbon parts having a particle size lower than 10 μm, the method comprising the steps of:
 a) positioning the carbon parts to be joined and a silicon element, said silicon element being inserted between said carbon parts, and 
 b) maintaining the assembly formed in step a) cohesive under pressure and subjecting it to heating at a temperature between 1410° C. and 1500° C. under an inert atmosphere for a period of 10 minutes to 1 hour, to melt the silicon and form a joint containing at least one silicon carbide bridge at an interface of said carbon parts, and 
 c) exposing the assembly obtained after step b) to a temperature higher than the temperature of step b) and between 1500° C. and 1750° C., for a period of 3 to 8 hours to consume all of the silicon and form a silicon carbide joint on the whole surface of the interface of said carbon parts. 
 
     
     
       2. The method as claimed in  claim 1 , wherein the silicon carbide joint obtained after step c) is completely devoid of residual solid silicon. 
     
     
       3. The method as claimed in  claim 1 , wherein the carbon parts have an open-cell porosity of 0 to 40% by volume. 
     
     
       4. The method as claimed in  claim 1 , wherein the carbon parts have a particle size of 1 to 5 μm. 
     
     
       5. The method as claimed in  claim 1 , wherein the joint formed at the interface of the two joined parts has a thickness between 10 and 40 μm. 
     
     
       6. The method as claimed in  claim 1 , wherein the silicon element in step a) is in the form of a silicon strip. 
     
     
       7. The method as claimed in  claim 1 , wherein the joint formed at the interface of the two joined parts has a thickness between 20 and 30 μm. 
     
     
       8. The method as claimed in  claim 1 , wherein step b) comprises the heating under inert atmosphere for 20 to 40 minutes. 
     
     
       9. The method as claimed in  claim 1 , wherein step b) is carried out at a temperature between 1430° C. and 1500° C. 
     
     
       10. The method as claimed in  claim 1 , wherein step c) is carried out at a temperature between 1600° C. and 1700° C.